Method For Making Elements Comprising Optical Fibers, Device For Implementing Said Method, Fiber Optic Element and Optical Device Comprising Same

ABSTRACT

Method for producing optical fibers elements disposed in defined positions, comprising the following steps, among others:
         placing the optical fibers in the grooves formed in a plate,   injecting a hardenable material between the grooved plate and the support plate,   solidification of the hardenable material to freeze the fibers in the position set by the grooves,   removing at least the grooved plate forming the mould.

FIELD OF THE INVENTION AND PRIOR ART

The present invention relates to a method for producing elementscomprising fiber optics in defined positions, to a device for theimplementation of said method, to the optical fibers elements obtainedthrough said method and to the optical arrangements, in particularoptoelectronics, comprising such elements.

Fiber optics are used in a number of optoelectronic devices such asoptical telecommunications devices, datacoms and optical sensors. Fiberoptics make it possible to guide optical beams between the various nodesand components used in these devices. Among these components, one maycite optical sources, detectors, spectrum analyzers, amplifiers,attenuators and switches. However, the connection between the ends ofthe fiber optics and the inlet or outlet of the component raises anumber of problems, which slows large-scale usage of such devices.

Currently, in order to obtain fiber optic assemblies, in which theoptical fibers are arranged in a precise manner in relation to eachother, media referred to as V-grooves in English terminology are used,provided with longitudinal V-shaped grooves, precisely adjusted, inwhich the fiber optics are positioned. This technique is described inU.S. document Pat. No. 6,795,634 B2. A counter-blade is then disposed onthe optical fibers opposite the V-groove arrays. A resin or glue is thenintroduced between the plate and the V-groove array. A unitary sandwichstructure is then obtained. The structure is parallelepiped in shape,from which the optical fibers come out, and can be easily manipulatedand positioned.

The V-groove arrays are made primarily by chemical etching usinglithography methods or by saw cut etching.

Although the production cost for groove array having a simple shaperemains commercially acceptable, it remains high relative to othertechnologies and prevents devices using optical fibers from trulyinteresting financially. Moreover, when the devices require specificdistributions of optical fibers, the production cost of V-groove arraysbecomes prohibitive.

Moreover, in the event the optical fibers element comprises opticalfibers distributed over several layers (matrix assembly of fibers),there is currently no simple production method.

It is consequently one object of the present invention to offer a simplemethod for producing optical fibers elements.

It is also one object of the present invention to offer a method forproducing optical fibers elements having a complex structure.

It is also one object of the present invention to offer a method forproducing optical fibers elements at a competitive production price.

DESCRIPTION OF THE INVENTION

The objects stated above are reached through a method in which theV-groove array is used as a reusable mould and not as a base integratedinto the final element. In this way, even if the mould has a complexshape and a high production cost, its repeated use makes it possible tocushion its cost and thereby to produce elements at a low productioncost.

In other words, the V-groove array no longer serves as a base, butrather solely as a mould, the optical fibers are maintained by ahardenable material and potentially by bases having simple shapes.

The fact of using a single mould improves the repeatability of themethod for producing the structure of the optical fibers element.

Moreover, this method enables the production of optical fibers elementshaving complex networks of optical fibers.

The present invention therefore relates to a method for producing anelement provided with several optical fibers disposed in definedpositions, comprising the following steps:

placing and maintaining optical fibers in grooves formed in a plate,

injecting a hardenable material adhering to the fibers,

solidification of the hardenable material to freeze the fibers in theposition set by the grooves,

removing at least the grooved plate forming the mould.

The hardenable material is, for example, a resin.

Advantageously, maintaining the fibers is also ensured by a supportplate, disposed on the optical fibers opposite the plate forming themould. The hardenable material can then be injected between the groovedplate and the support plate.

Advantageously, the method according to the invention makes it possibleto form a optical fibers element having a matrix structure be repeatingthe steps listed above.

Furthermore, the method according to the present invention alsocomprises a step for solidification of the hardenable material, forexample, by luminous insolation or heating of the hardenable material.

Advantageously, luminous insolation of the resin is done in ultravioletand the plate forming the mould and/or the support plate is made of amaterial transparent to ultraviolet rays.

In one example, the method according to the present invention may alsocomprise a step for gluing a support plate instead and in place of themould plate.

In another example, the method according to the invention comprises astep for gluing the element directly on a transfer structure of anoptical device. In this case, the transfer structure may comprisegrooves corresponding to the grooves of the mould plate. This enablesinterpenetration between the optical fibers element and the structure,and ensures defined positioning between the optical fibers element andthe structure. The interface between the transfer structure and theoptical fibers element may also be flat.

In another example, the transfer structure or the support platecomprises a trench sized such that, at the beginning of the gluing step,the optical fibers element only rests on the transfer structure or onthe support plate by its lateral ends.

Advantageously, the optical fibers are cleaved before their positioningin the mould plate.

The production method according to the invention may also comprise astep for polishing the ends of the optical fibers; advantageously, thisstep for polishing the ends of the optical fibers takes place beforeremoval of the plate forming the mould.

The present invention also relates to a device for implementation of themethod according to the invention, characterized in that it comprises atleast one mould plate provided with first longitudinal grooves on afirst surface, and in that said first surface has low adhesionproperties with regard to the hardenable material intended to beinjected between the mould plate and the support plate.

In one embodiment, the mould plate also comprises two longitudinalgrooves which depth is greater than that of the first longitudinalgrooves.

For example, the first surface receives a C₄F₈ or OMCTS or SiOC typetreatment obtained by plasma deposition process.

According to one embodiment, the grooves have different depths so as todefine distinct parallel planes for the optical fibers.

According to another embodiment, the grooves are located in the bottomof a trench, said trench forming, on the surface of a first opticalfibers element, positioning means relative to a second mould plate.

Advantageously, the second mould plate comprises a flat-bottomed trench,so as to obtain, after moulding on the first optical fibers element of aflat surface, a second optical fibers element provided with a flatsurface.

Furthermore, the device comprises a third mould plate provided with atrench having a grooved bottom so as to receive optical fibers, thedepth of the trench being such that when the second element is placed inthe trench, the flat surface of the second element bears on the opticalfibers.

Advantageously, the mould plate(s) comprise(s) trenches for supplyingthe grooves with resin.

Preferably, the trenches have a trapezoidal cross-section.

The mould plates may be formed in a silicon substrate chemically etchedby photolithography etching process or using a saw.

For example, the grooves have a V-shaped cross-section, the branches ofthe V forming a 70.6° angle, and the grooves are spaced from each otherat a distance of 250 μm, corresponding to an optical fiber size.

The present invention also relates to a optical fibers element obtainedusing a method according to the invention.

Advantageously, the support blade is in glass, and particularly inpyrex®.

In one advantageous example, the optical fibers element comprises asupport blade provided with a trench under of and in a straight line ofthe optical fibers.

In one particular example, the support blade comprises a surface formedby at least two offset parallel planes and intended to bear on theoptical fibers disposed in the corresponding offset parallel planes.

The present invention also relates to a fiber optic device comprising anelement according to the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be better understood with the help of thedescription below and the annexed figures, for which the top and bottomcorrespond to the upper and lower parts of the drawing, respectively,and in which:

FIG. 1 a is a perspective view of a optical fibers element obtainedusing a method according to the present invention,

FIG. 1 b is a perspective view of a optical fibers element of the priorart,

FIGS. 2 a to 2 f are steps in an example of a method according to thepresent invention,

FIGS. 3 a to 3 c are steps of another example of a method according tothe present invention,

FIGS. 4 a to 4 f are steps of another example of a method according tothe present invention for producing an element comprising optical fibersdisposed in distinct planes,

FIGS. 5 a to 5 h are steps of still another example of a methodaccording to the present invention for producing an element comprisingoptical fibers assembled in a matrix,

FIG. 6 is a perspective view of a mould plate for implementation of themethod according to the present invention,

FIGS. 7 a and 7 b are steps in the production of a device provided witha optical fibers element according to the present invention,

FIG. 7 c is a perspective view of an optical device from the state ofthe art,

FIGS. 8 a to 8 c are steps in the formation of a optical fibers elementaccording to the present invention,

FIGS. 9 a to 9 e are steps in another example of a production methodaccording to the present invention for an element comprising opticalfibers assembled in a matrix,

FIGS. 10 a to 10 f are steps in another example of a production methodaccording to the present invention for a optical fibers element,

FIGS. 11 a to 11 f are steps in another example of a production methodaccording to the present invention for a optical fibers element.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

In figure la, one can see an example of a optical fibers element 2according to the present invention, comprising optical fibers 4 alignedfollowing a longitudinal direction X and maintained in a definedposition by a holder 6 in resin. This assembly 2, according to thepresent invention, does not comprise, contrary to the optical fiberselements 2′ of the state of the art, whereof one element is illustratedin FIG. 1 b, a support plate 8 provided with V-shaped grooves 10, inwhich the optical fibers are positioned before being submerged in aresin, the support plate then being a permanent part of the opticalfibers element.

In FIGS. 2 a to 2 f, we can see the different steps of an example of amethod according to the present invention, comprising the followingsteps:

placing several optical fibers 4 in the grooves 112 of a grooved ormould plate 100,

depositing a support plate 14 on the optical fibers opposite the mouldplate 100,

injecting a hardenable material between the mould plate 100 and thesupport plate 14,

processing the hardenable material so as to harden it,

removing the mould plate 100.

We will now describe the method according to the present invention indetail.

The mould plate 100, having a substantially rectangular shape, compriseslongitudinal grooves 112 made in an upper surface 104 of the plate 100.In the illustrated example, the grooves have a V-shaped cross-section(FIG. 2 a).

The optical fibers 4 have the shape of a long regular cylinder, relativeto their diameter.

The optical fibers 4 are disposed in the grooves 112 such that, on across-section, the optical fiber rests in the groove 112 in two points Aand B. The support plate 14, formed for example from a flat blade,called a counter-blade, is deposited on the optical fibers opposite themould plate 100 and is in contact with each of the fibers at a point Cwhen considering a cross section (FIG. 2 b). The positioning of eachfiber is thereby generally ensured to within about 1 μm. The supportplate 14 has a shape adapted to maintaining fibers in the grooves 112during the steps for injection and hardening of the resin, regardless ofthe shape of the mould plate and the distribution of the fibers. Othermaintaining means allowing later removal of the mould plate may also beused.

In another step, a resin 16, for example of the liquid polymer type, ormore generally a hardenable material, liquid having a greater or lesserviscosity, adhering to the optical fibers, for example a suitablesol-gel, is then injected between the mould 100 and the support plate14. This resin penetrates all of the space defined between the mould 100and the support plate 14, in particular between the mould 100 and theoptical fibers. Advantageously, trenches 18 for supplying resin, etchedin the mould 100 (FIG. 6), allowing the resin to circulate toward thegrooves may also be made. The resin can also be deposited prior topositioning of the support plate.

The resin 16 is then solidified, for example by cross-linking. Dependingon the type of resin used, cross-linking is obtained by luminousinsolation, for example in ultraviolet (UV) and/or by heating, or usingany other method known by one skilled in the art depending on the typeof hardenable material used. In the case of luminous insolation, it ispreferable to use transparent materials in the concerned spectral band,to produce the mould 100 and/or the support plate 14. Advantageously,the support plate 14 is made of glass, in particular pyrex®, which iseffectively transparent to UV rays.

As an example, one type of polymer resin that may be used is an epoxyresin under the trade name EPO-TEK OG198-50® marketed by the CompanyEPOTEK.

When the resin 16 is solidified, the element 102 formed by the opticalfibers 4 trapped in the solid resin 16 and the counter-blade 14, isextracted from the mould 100 (FIG. 2 d). To perform this extraction, amould 100 is anticipated whereof the surface 104 intended to be incontact with the resin 16 preferably has low adhesion or anti-adhesionproperties relative to the resin, so as to enable easier extraction ofthe optical fibers element. For this purpose one may anticipate, forexample, applying a treatment to the mould plate 100 such that it doesnot adhere to the resin. This may, for example, be a C₄F₈-type treatment(perfluorocyclobutane) obtained by plasma deposition process or am OMCTS(Octamethylcyclotetrasiloxane) or SiOC treatment, also obtained byplasma deposition process known by those skilled in the art.

Preferably, this type of treatment guarantees, in addition to thenon-adherence of the resin cross-linked on the first support 100,sufficient mouldability to allow the non-cross-linked resin tocompletely fill the space defined by the plates 100, 14.

All of the mould plates used as moulds in the different examples of amethod according to the present invention can be treated in the mannerdescribed above or in a similar manner, such that they have thisanti-adhesion property, or at least low adhesion relative to the resin.

In the example described above, the support plate 14 is an integral partof the optical fibers element, which makes it possible to stiffen it.For this, it is preferable for the resin to adhere well to this supportplate 14. However, it is understood that one may also remove thissupport plate 14. To this end, prior treatment, as previously described,may be done on the support plate 14.

In order to increase the stiffness of the element 102, one may alsodispose, on the lower surface 106 of the element 102, previously incontact with the mould plate 100, a second support plate 22. In order tomake this second plate 22 integral with the assembly 102, one againinjects a resin between the second support plate 22 and the element 102;this resin can be the resin 16 previously used or another resincompatible with the resin 16, and more generally another material ofgreater or lesser viscosity, able to solidify (for example a sol-gel)and compatible with the first material used to maintain the opticalfibers.

A solidification treatment is then done in the same way as previously.One then obtains a optical fibers element 108 comprising flat upper andlower surfaces, very easy to manipulate.

It is understood that the addition of the second support plate 22 to theelement 102 can be avoided, particularly in the case where, for example,the element 102 is intended to be made integral on a structure 24 of adevice 26, which itself ensures the stiffness of the element 102 (FIGS.3 a to 3 c). Making the element 102 integral with the structure 24 isdone, for example and as previously described, by inserting resin andsolidifying it.

If the fibers have been cleaved prior to being buried in the resin 16,meaning if their ends have been cut so that the optical beams coming outof the fibers are not deformed by passing through the refractingsurface, and if the precision of the alignment of the fibers at the endof the assembly is sufficient for the desired application, the opticalfibers element can be used directly in a device or marketed.

However, if the fibers are not cleaved or if the alignment of the endsof the fibers is not sufficient, one may polish using the normaltechniques for polishing optical fibers, not described here.

If one wishes to perform polishing, the element 102.1 comprising firstand second support plates is advantageous because it is easier tohandle.

It should be noted that some of the resins that may be used to producethe elements according to the present invention have the characteristicof undergoing a removal during their cross-linking. It is thenpreferable to take this removal into account during the creation of theV-grooves.

The first support plate is, for example, made of a silicon substrate, onthe upper surface of which the V-grooves and the circulation channelsare etched, for example by photolithography. During sizing of the mouldplate, the diameter of the stripped fiber is taken into account, forexample 125 μm, as well as the desired pitch between the fibers, whichis typically, for the aforementioned diameter of the stripped opticalfibers, approximately 250 μm (value preferably corresponding to thediameter of the non-stripped fiber). The dimension of the V-groovesdepends on the production technology selected. In particular, withchemical etching of the silicon, the sides of the grooves form a 54.7°angle relative to the surface of the substrate, and the size of theopening of the grooves is therefore calculated accordingly.

In FIGS. 4 a to 4 f, one can see an example of a method for producing aoptical fibers element 202, wherein the optical fibers 4.1 and 4.2 aredisposed parallel to each other, and are contained in a plane Pa and ina plane P2 respectively, the planes P1 and P2 being parallel andseparate. In this case, it appears that producing such an element usingtraditional techniques has a very high production cost. The presentinvention is then very interesting.

The mould plate 200 comprises grooves 203 having a V-shapedcross-section, but contrary to the preceding examples, the grooves212.1, 212.2 have different depths. In the example of the optical fiberselement containing two plates P1, P2 for two optical fibers 4.1, 4.2,the mould plate 200 comprises a first pair of grooves 212.1 having afirst depth h1, and a second pair 212.2 of grooves having a second depthh2, h1 being greater than h2. Thus, during extraction, the fibers 4.1are disposed in the plane P1, located below the plate P2 containing thefibers 4.2

In FIG. 4 b, one can see a second support plate 214 comprising a surfaceintended to come into contact with the optical fibers, defined by twoplanes 214.1, 214.2 offset so as to follow the optical fibers 4.1, 4.2contained in the planes P1, P2, respectively. Likewise, in FIG. 4 f, inthe case where a second support plate 222 is used, said second supportplate also has an adapted profile. One obtains (FIG. 4 e) an element202.1 provided with only one support plate and an element 202.2 (FIG. 4f) provided with two support plates on either side of the layer ofresin.

The following steps illustrated in FIGS. 4 c to 4 f are similar to thosedescribed for the preceding examples.

In FIGS. 5 a to 5 g, one can see an embodiment of an element 302 withoptical fibers distribution in a matrix or in parallel layers. This typeof element is, according to the known techniques, very problematic toproduce, since the support plates in which the V-shaped grooves are madeare only easy to etch on one of their surfaces.

The method according to the present invention makes it possible toproduce this type of element with matrix distribution by using onlymould plates provided with grooves on just one surface.

In FIGS. 5 a and 5 b, one can see a first mould plate 300.1, providedwith a trench 303 in the bottom of which V-shaped grooves 312 are made.Optical fibers 4 are disposed in the grooves according to a first layerC1. A support plate 14 is then disposed on the optical fibers. The resin16 is then injected between the mould plate 300.1 and the support plate14. The mould plate 300.1 is then removed. The intermediate opticalfibers element 302.1 thereby obtained comprises, on one surface 306opposite the support plate 14, a step-profile 308 provided with V-shapedprotuberances 310 (FIG. 5 c).

In FIG. 5 d, one can see the intermediate element 302.1 disposed on asecond mould plate 300.2, the step 308 forming means for aligning theintermediate optical fibers element relative to a trench 314 formed inthe second mould plate 300.2. The trench 314 is provided with a flatbottom having a depth greater than the height of the V-shapedprotuberances 310.

The intermediate element 302.1 and the second plate 300.2 then define acavity 316, wherein the resin is injected in the step illustrated inFIG. 5 e. This resin is then solidified as previously described. Asecond intermediate element 302.2 is then obtained after extraction,comprising a flat surface 317 opposite the support plate 14 (FIG. 5 f).

In FIG. 5 f, one can see a step for producing a second layer C2 ofoptical fibers in a plane parallel to the first layer C2. To do this,the intermediate element 302.2 is disposed in a third mould plate 300.3or mould. The mould 300.3 comprises a trench 318, in the bottom of whichV-grooves are formed and wherein optical fibers are disposed. The flatsurface 317 of the second element 302.2 bears on the optical fibers, andthe fibers are again kept in contact by three points. Advantageously,the second intermediate element 300.2 comprises alignment means 220cooperating with the alignment means 321 of the mould 300.3, allowingprecise and automatic positioning of the second element relative to themould. In the illustrated example, the means 321 are formed by a secondbeveled surface cooperating with surfaces having the same slopesupported by the mould 300.3 and forming the means 322.

The resin 16 is then injected between the third mould 300.3 and thesecond intermediate element 302.2, then this resin is solidified. Aoptical fibers element 302.3 comprising a distribution of optical fibersaccording to the parallel layers C1 and C2 is obtained after extraction.

An additional step for association with another flat support plate 322to stiffen the assembly may be carried out as already described (FIG. 5h).

In the illustrated example, the trenches advantageously have atrapezoidal cross-section forming means for guiding the optical fiberselements in the mould plates during the different stages of the method.

It is understood that one can make more than two layers, for which oneneed only repeat steps 5 d to 5 f.

Modifying the orientation of the fibers from one layer to another so asto have, for example, an orthogonal orientation of the fibers of onelayer relative to the fibers of the next layer, is not beyond the scopeof the present invention.

In FIG. 7 c, one can see a fiber optic device from the state of the artprovided with a substrate forming a non-removable support plate forminga unit with the fiber optic unit 2′. Collective polishing of the ends ofthe fibers is then not possible. In this case, it is thereforeanticipated to cleave the fibers and put them at a distance from thecomponent stick that one wishes to combine. Cleaving, however, causes aslight angle which means that the ends of the fibers are not allstrictly parallel, which can create dispersion on the coupling ratio.

The present invention proposes a simple solution enabling precisepositioning of the optical fibers relative to the collecting strip.

On FIGS. 7 a and 7 b, one can see an embodiment of a fiber optic device401, wherein a optical fibers element obtained according to a methodaccording to the invention is assembled. The element 402 is similar tothat obtained during the steps shown in FIGS. 2 a to 2 d. The element402 comprises a resin part 404 in which the optical fibers are immersedprovided on a surface of a counter-blade 14 and on an opposite surface406 of V-shaped protuberances 408. The device 401 comprises a substrate410 in which V-grooves 412 are made corresponding to the outside profileof the protuberances 408 and identical to the grooves of the productionmould 100. The grooves 412 form means for precise positioning of theelement 402 relative to the substrate 410.

In a following step (FIG. 7 b), the element is glued on the structuredsubstrate 410. This embodiment then guarantees optimal alignment of thefibers in relation to the substrate 410 while also enabling collectivepolishing of fibers before transfer of the element on the substrate.

Polishing the fiber assembly is preferably done before removal of themould plate 100 so as to avoid ungluing of the fibers from thecounter-blade 14 or pollution of the V-groove arrays 408 by polishingresidue, which would disrupt the positioning of the optical fiberselement on the substrate.

In FIGS. 8 a to 8 c, an additional advantage of the production methodaccording to the present invention is explained. This makes it possible,very advantageously, to polish the fibers simultaneously according to aplane forming a non-right angle with the longitudinal direction of thefibers 4, without risking changing the orientation of the fibers inrelation to each other. On the contrary, in the optical fibers elementsof the state of the art, individual polishing must be done for eachfiber, then the fibers must be disposed in relation to each other whileensuring the alignment of the ends of the optical fibers.

Since polishing can be done on limited areas of the mould plate 100, themould plate 100 can be reused later. Moreover, it is also possible topolish the counter-blade 14 prior to assembly, such that only theoptical fibers 4 are polished at this stage.

In FIGS. 9 a to 9 e, one can see the production of a optical fiberselement 502 having a sandwiched matrix structure made up of a pile ofbase structures 102. In other words, the element 502 comprisesalternating layers of optical fibers 504 maintained through the resinand a counter-blade. The stages of production correspond to a repetitionof a sequence of steps illustrated in FIGS. 2 a to 2 f, and whichtherefore will not be described in detail.

In the illustrated example, two types of counter-blades are used, afirst type 14 as already described and defining the upper and lower endsof the element, and a second type of counter-blade 514, thinner andintended to be disposed between two layers of resin. But it isunderstood that using only one type of counter-blade is not beyond thescope of the present invention.

This embodiment offers the advantage of stiffening the optical fiberselement 502. Moreover, this makes it possible to obtain regular spacingbetween the layers of fibers simply.

In FIGS. 10 a to 10 f, one can see the different stages in anotherparticularly advantageous example of a method according to the presentinvention.

The steps illustrated in FIGS. 10 a to 10 d are identical to those ofthe method from FIGS. 2 a to 2 f.

At step 10 e, the element illustrated in FIG. 10 d is made integral witha support plate 622, while ensuring very good alignment of the plates.

Indeed, in the method illustrated in FIGS. 2 a to 2 f, the parallelismof the plates 14 and 22, and therefore of the planes of the fibersrelative to the support plate and/or to a transfer structure, isobtained through contact of the ends of the of the protruding ribs ofthe element 102, these ends having point-shape, these points beingcontained in a plane parallel to the plate 14. These V-shaped ribs arevery fragile mechanically. One of the ends having point-shape may break;it cannot be longer guaranteed that the planes of the optical fibers andthat of the support plate 22 are parallel.

This problem is particularly sensitive in the case where one wishes todirectly interface the optical fibers element, also called fiberV-block, with optical components opposite it, wherein fiber positioningprecision lower than 3 μm, or even lower than 1 μm, may be required.

One then uses a support plate 622 provided with a trench 615, having adepth sufficient to avoid contact between a bottom 615.1 of the trenchand the points 611, the element 612 only resting on the support plate622 by its flat lateral ends 612.1, ensuring that the plate 14 and theplate 622 are parallel.

The trench may be formed very crudely and does not require anyparticular precautions, since the shape of the walls does not play arole in the precision of the parallel disposal. Thus, in the illustratedexample, the trench 615 has a very irregular shape, and its productionmay be done quickly, maintaining a low production cost.

The support plate 622 can be replaced by a transfer structure of anoptical device.

This method also offers the advantage of reducing the quantity of resinused; since the volume to be filled with resin is that of the trench615, and not that of the space defined between the support plate 22 andthe element 102 of FIG. 2, which extends the width of the plates 22,102.

In FIGS. 11A to 11F, one can also see another very advantageousproduction method, making it possible to ensure that a support plate 714and an element 702 are parallel.

In this case, a mould plate 700 comprising V-grooves 712 and a first andsecond lateral groove 713.1, 713.2 parallel to the V-grooves 712, thegrooves 713.1, 713.2 having a depth greater than that of the grooves 712can be used. Moreover, these 713.1, 713.2 comprise a flat bottom so asto allow moulding of non-fragile, flat bottomed ribs.

In the illustrated example, the grooves 713.1, 713.2 are disposed oneither side of the V-grooves, but one can dispose them between theV-grooves 712, if the distribution of the optical fibers allows.Moreover, one can provide for more than two grooves.

The production steps are similar to those of steps 2 c to 2 f. However,during the step illustrated in figure lie, the element 702 rests on thesupport plate 714 on ribs 715 parallel to the V-ribs obtained from thegrooves 713.1, 713.2 of the mould plate 700, and not on the ends of theV-ribs.

This method may be used to produce elements with optical fibersdistributed in a sandwich matrix such as in FIG. 9 e, by applying thesteps from FIGS. 9 a to 9 e, with a mould plate 700 similar to thatdescribed below.

Thus, great precision in positioning relative to the layers of opticalfibers may be obtained thanks to this embodiment.

The combination of examples of method according to the present inventionor only some of these steps is not beyond the scope of the presentinvention.

Moreover, the present invention is not limited to a parallel arrangementof fibers, but also extends to a divergent or convergent arrangement ofone or several fibers relative to the others.

Furthermore, the use of mould plates provided with grooves have aU-shaped cross-section, for example, or any other shape ensuring thedesired positioning of the optical fiber, is not beyond the scope of thepresent invention.

1-29. (canceled)
 30. A method for producing an element provided withseveral optical fibers disposed in defined positions, comprises thefollowing steps: placing and maintaining optical fibers in groovesformed in a plate, injecting a hardenable material adhering to thefibers, solidification of the hardenable material to freeze the fibersin the position set by the grooves, removing at least the grooved plateforming a mould.
 31. A production method according to claim 30, whereinmaintaining of the fibers is also ensured by a support plate, disposedon the optical fibers opposite the plate forming a mould.
 32. Aproduction method according to claim 31, wherein the hardenable materialis injected between the grooved plate and the support plate.
 33. Aproduction method according to claim 30, wherein the solidification stepis done by luminous insolation or heating of the hardenable material.34. A production method according to claim 33, wherein the luminousinsolation of the hardenable material is done in ultraviolet and whereinthe mould plate and/or the support plate is made of a materialtransparent to ultraviolet rays.
 35. A production method according toclaim 30, also comprising a step for gluing a support plate instead andin place of the grooved.
 36. A production method according to claim 30,comprising a step for gluing the element directly on a transferstructure of an optical device.
 37. A method for producing a opticalfibers element having a matrix structure, comprising the repetition ofsteps according to claim
 30. 38. A production method according to claim36, wherein the transfer structure comprises grooves corresponding tothe grooves of the mould plate, to receive the optical fibers element,so as to have interpenetration of the optical fibers element and thestructure ensuring positioning between the optical fibers element andthe structure.
 39. A production method according to claim 36, whereinthe interface between the transfer structure and the optical fiberselement is flat.
 40. A production method according to claim 36, whereinthe transfer structure or the support plate comprises a trench sizedsuch that, at the beginning of the gluing step, the optical fiberselement only rests on the transfer structure or on the support plate byits lateral ends.
 41. A production method according to claim 30, whereinthe optical fibers are cleaved before their positioning in the mouldplate.
 42. A production method according to claim 30, also comprising astep for polishing the ends of the optical fibers.
 43. A productionmethod according to claim 42, wherein the step for polishing the ends ofthe optical fibers takes place before removal of the plate forming themould.
 44. A device for implementing the method for producing an elementprovided with several optical fibers disposed in defined positions,comprises the following steps: placing and maintaining optical fibers ingrooves formed in a plate, injecting a hardenable material adhering tothe fibers, solidification of the hardenable material to freeze thefibers in the position set by the grooves, removing at least the groovedplate forming a mould, said device comprising at least one mould plateprovided with first longitudinal grooves on a first surface, and in thatsaid first surface possesses low adhesion properties regarding thehardenable material intended to be injected between the mould plate andthe support plate.
 45. A device according to claim 44, wherein the mouldplate also comprises second longitudinal grooves having a depth greaterthan that of the first longitudinal grooves.
 46. A device according toclaim 44, wherein the first grooves have different depths so as todefine separate parallel planes for the optical fibers.
 47. A deviceaccording to claim 44, wherein the first grooves are made in the bottomof a trench, said trench forming, on the surface of a first opticalfibers element, positioning means relative to a second mould plate. 48.A device according to claim 47, wherein the second mould plate comprisesa trench having a flat bottom so as to obtain, after moulding on thefirst fiber element of a flat surface, a second optical fibers elementprovided with a flat surface.
 49. A device according to claim 48,comprising a third mould plate provided with a trench having a groovedbottom so as to receive the optical fibers, the depth of the trenchbeing such that when the second element is placed in the trench, theflat surface of the second element bears on the optical fibers.
 50. Adevice according to claim 47, wherein the trenches have a trapezoidalcross-section.
 51. A device according to claim 44, wherein the groovedplate(s) comprise(s) trenches for supplying the grooves with hardenablematerial.
 52. An optical fibers element characterized in that it isobtained through the following production method comprising thefollowing steps: placing and maintaining optical fibers in groovesformed in a plate, injecting a hardenable material adhering to thefibers, solidification of the hardenable material to freeze the fibersin the position set by the grooves, removing at least the grooved plateforming a mould.
 53. An optical fibers element according to claim 52,wherein the support blade comprises a trench under of and in a straightline of the optical fibers.
 54. An optical fibers element according toclaim 52, wherein the support blade comprises a surface formed by atleast two distinct parallel planes and intended to bear on the opticalfibers disposed in corresponding offset parallel planes.